Polyphosphate Wrapper Paper for Flame Resistance and Strength

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Solution Overview

Problem

Existing wrapper papers for aerosol-generating articles are either not sufficiently heat-resistant or flame-retardant, leading to potential tearing during use, increased risk of fire, and environmental impact due to non-biodegradability, while also affecting taste and manufacturing processability.

Innovation Solution

A wrapper paper comprising at least 55% pulp fibers and 5-30% polyphosphates, with a preferred distribution of polyphosphates for enhanced flame-retardancy and strength, and optionally combined with additional layers for improved properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the wrapper paper is coated with calcium carbonate and binder to achieve heat resistance, then the wrapper paper becomes brittle and generates dust, but the tensile strength is reduced

Engineering Contradiction:
Improveheat resistanceVSAvoidtensile strength
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The patent changes the chemical composition parameters by replacing calcium carbonate coatings with polyphosphate additives at controlled concentrations (5-30% by mass). This parameter change maintains heat resistance while preserving tensile strength, as polyphosphates provide flame retardancy without the brittleness associated with thick calcium carbonate coatings.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system combining pulp fibers with polyphosphate additives. This composite approach allows the wrapper paper to achieve both heat resistance and adequate tensile strength, as the polyphosphates work synergistically with the pulp fiber matrix to provide thermal stability without compromising mechanical properties.

Inventive Principle:
Principle #40Composite materials

2Temperature

If aluminum foil is added to the wrapper paper laminate to protect from heat, then the wrapper paper gains heat protection, but the manufacturing process becomes complex and biological degradability is reduced

Engineering Contradiction:
Improveheat protectionVSAvoidmanufacturing process complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent extracts and removes the aluminum foil layer from the wrapper paper composition. Instead of using metal foil for heat protection, the invention relies on polyphosphate additives incorporated into the paper matrix, which provide flame retardancy and heat resistance without requiring complex laminate structures or metal processing.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a simple, biodegradable paper-based solution with polyphosphate additives rather than persistent aluminum foil. This approach prioritizes environmental degradability and simplifies the manufacturing process, accepting that the wrapper paper is disposable and will decompose naturally after use.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Strength

If the wrapper paper has high pulp fiber content to maintain strength, then the tensile strength increases, but the flame-retardant effect may be reduced

Engineering Contradiction:
Improvetensile strengthVSAvoidflame-retardant effect
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes the concentration parameter of polyphosphate additives within the range of 5-30% by mass. This parameter optimization ensures sufficient flame-retardant effect while maintaining adequate tensile strength. The polyphosphates act as flame retardants at these concentrations without excessively compromising the mechanical strength provided by the pulp fiber matrix.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The wrapper paper maintains mechanical strength and prevents combustion, is biodegradable, and does not affect taste, while ensuring safe handling and manufacturing efficiency.

Implementation Method 1

Polyphosphates are hygroscopic and thus absorb moisture from the atmosphere. This has a beneficial effect in terms of flame retardancy, as combustion can generally only start if the material is relatively dry.

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

the wrapper paper of the aerosol-generating article is required to have flame-retardant properties... the wrapper paper according to the invention has an improved flame retardation compared to known heat-resistant wrapper papers

Methodology Applied
Scientific EffectFlame retardancy:

Data Source

PatentUS12604924B2Wrapper paper with improved flame resistance
Publication Date: 2026.04.21 DELFORTGROUP

AI summary

A wrapper paper is described that is suitable for use on aerosol-generating articles and which comprises pulp fibers and one or more polyphosphates, wherein the pulp fibers make up at least 55% and at most 95% of the mass of the wrapper paper and the polyphosphates are together contained in a concentration of at least 5% and at most 30% with respect to the mass of the wrapper paper. In this regard, the polyphosphates are compounds with the molecular formula Mn+2PnO3n+1 or Mn[H2PnO3n+1], wherein n is at least 2 and at most 100 and M is a monovalent metal or ammonium (NH4+).